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M AY 2 0 1 4 | O U T P AT I E N T S U R G E R Y M A G A Z I N E O N L I N E
Great ideas for your OR
The new system, using an algorithm that the research team had pre-
viously constructed to help spine surgeons navigate vertebral levels,
automatically matches 2D fluoroscopic images to 3D CT scans and
updates them throughout the case.
"Rather than adding complicated tracking systems and special mark-
ers to the already busy surgical scene, we realized a method in which
the imaging system is the tracker and the patient is the marker," says
Dr. Siewerdsen.
Testing the system on cadavers, the team has found that its results
are consistently more precise than those of existing systems, deliver-
ing better than 2mm of accuracy as compared to a standard of 2mm
to 4mm. They're currently working to translate their methods into a
system that can be studied by a wider clinical audience.
"The breakthrough came when we discovered how much geometric
information could be extracted from just one or two X-ray images of
the patient," says computer science graduate student Ali Uneri. "From
just a single frame, we achieved better than 3 millimeters of accuracy,
and with 2 frames acquired with a small angular separation, we could
provide surgical navigation more accurately than a conventional
tracker."
Better still: the system can derive this navigational information
from images taken with an extremely low dose of radiation, expos-
ing the patient to even less radiation than a routine intraoperative
image would.
— David Bernard
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